FILE - This Oct. 5, 2016 file photo shows Dale Hall, dressed as Superman, next to the casket for his brother, Jacob Hall at Oakdale Baptist Church on Wednesday, Oct. 5, 2016, in Townville, S.C. A teenager charged with killing his father at their home and a first-grader on a school playground said he kissed his bunny Floppy and three dogs goodbye after shooting his father and then headed to the school to resume shooting, according to the boy's videotaped statement played in court Monday, Feb. 12, 2018. (Ken Ruinard/The Independent-Mail via AP, Pool)

ANDERSON, S.C. (AP) — When a teen began firing at students on a South Carolina elementary school's playground, the principal said her horror became even worse when she recognized him as a former student.

"He's been here. He knows where our kids are. He knows how we drill," Townville Elementary School Principal Denise Frederick testified on Tuesday.

News outlets reported that Frederick took the stand at a hearing to determine if the teen will be tried as an adult for two counts of murder — one for the September 2016 shooting of his father in their home, and another for the first grader killed at the school a short while later.

The teen, who turned 14 just weeks before the shootings, surrendered without entering the school. In an interview with investigators played in court Monday, he said he loaded the wrong ammunition into the gun, and it jammed each time he fired at the school playground.

He said he thanked God for the gun jams, saying it prevented him from shooting more people.

Jacob Hall, 6, was shot in the leg and bled to death. A teacher was wounded in the shoulder and another student was hurt, but both survived.

Prosecutors want the teen tried as an adult, where he could face decades in prison if convicted. His attorneys want him tried as a juvenile, where he could be held only until his 21st birthday if found guilty.

The Associated Press is not using the defendant's name while he remains in the juvenile court system.

Later Tuesday, prosecutors showed the judge surveillance video from the shooting that showed panicked children trying to get back inside. They also showed crime scene photos with an investigator pointing out details such as cupcake icing from treats, made by one student's grandmother, that the youngsters had been getting ready to eat.

The judge told reporters they could not show the video or photos outside the courtroom.

The teen's lawyers asked Frederick what she knew about his chaotic home life. He told investigators his father was a drunk who had loud arguments with his mother and tried to fight him. He said he spent most of his time locked in his room, posting to social media or petting his bunny.

Don Smith, a lawyer assigned to be the teen's guardian, suggested in questions Monday that the teen's father might have had him kill chickens that weren't growing fast enough at the family's home. School officials did not know, and the guardian Smith did not elaborate.

The shooting forever changed Townville Elementary School, Frederick said, recalling a school event where a balloon popped, bringing back horrible memories for dozens.